Hi,My customer & invoice data has disappeared from the app on my phone but is still on the desktop version. Any ideas how to retrieve the data would be great.Thank you

We can perform troubleshooting steps to help fix the missing data in your mobile app,tom-a24propertym. 

When the application is not fully functional, it's recommended to clear its cache files. This is a helpful initial step to resolve any sort of errors.

Follow these steps if you're using an iOS device:

1. Tap the Burger icon or 3 horizontal lines at the bottom-right.
2. Look for the the Question mark in the upper-right hand corner and tap on it
3. Tap Refresh data.

For Android devices:

1. Tap More Options or the three dot ⋮, select Settings, and then tap Refresh Data.
2. Click Yes.

Once refreshed, restart your mobile phone, and check if you'll be able to view the data. Just in case the issue persists., uninstall and reinstall the QuickBooks Online mobile app. Let me share this article with you for additional reference: Mobile App FAQs.

All hands are open to help you in case you need further guidance with this process. Have a great day!